2d6 Sword and Sorcery from Two Hour Wargames is available as a free pdf download. It is designed as a beer-and-pretzels style adventure game.
fantasy
Frostgrave House Rules
Here are a set of houserules for Osprey Publishing’s Frostgrave.
Full Command Fantasy Warfare
Full Command Fantasy Warfare is a set of free wargames rules for hex-based fantasy games.
Pocket Tactics 3D Printer Game
Pocket Tactics is a free download and print on your 3D printer game.
I think this is the wave of the future.
GURPS Treasure Generator
For GURPS players, here is an online automated treasure generator.